Tube drawing



Dec. 27, 1932. WEBER 1,892,477

TUBE DRAWING Filed DEC. 18, 1950 5 Sheets-Sheet l :NVENTQR 144% 75/? C. WEBER.

ATTORNEY Dec. 27 1932. w WEBER 1,892,477

TUBE DRAWING Filed Dec. 18, 1950 3 Shees-Sheet 2 INVENTOR BY W171 TERCJVEBEIQ ATTORNEY Dec. 27, 1932. w. c. WEBER 1,892,477

TUBE DRAWING Filed Dec. 18, 1950 3 Sheets-Sheet 3 w w wwm ATTOR N EY lNVENTOR WflZi'Z-WC. WEIEER.

Patented Dec. 27, 1932 UNITED STATES, PATENT orr'lcr.

WALTER C. WEBER, OF CORNING, NEW YORK, ASSIGNOR TO COBNING GLASS WORKS, OI CORNING, NEW YORK, A CORPORATION OF NEW YORK "TUBE DRAWING 'RElSSUED Application filed December 18 1930. 5 Serial No. 503,293.

This invention relates to glass drawing, and more particularly to the manufacture of glass tubing by flowing the molten glass over the crest of an annular curb projecting upwardly from the bottom of a container; of molten glass, the interior of the curb forming a glass flowing orifice, atsuch head that the flowing glass does not fill the orifice but issues therefrom in a hollow stream. Inside the stream so formed means are provided for chilling the inner surface of the stream by radiation from a cooling element while, if; desired, means may be provided for re-heating the exterior of the stream after it moves-from 03 the curb to fire-finish it. The head of glass at the crest of the curb is preferably set out in the following disclosure and shown in the accompanying drawings, inwhich:

Fig. 1 is aside elevation of my apparatus; Fig. 2 is a plan view of my apparatus; Fig. 3 is a sectional view taken along the line 3-3 of Fig. 2. v

Referring to the drawings in detail, a base 10, rectangular in form and constructed preferably of channel girders is supported on de:

pending journal members 11 in which wheels 12 are axeled, the wheels providing mov-:

ability for the apparatus. Secured to the base are four angle irons 13 supporting a channeled casting 14, which is formed with a large circular opening in its center surrounded by a flange 15 (Fig. 3). This casting is provided on its upper surface adjacent the flange 15 with a ball race 16. A gear 17 fits rotatably around the flange 15 and is provided with a ball race 18 which coacts with the ball race 16 and balls19 to form an antifriction bearing. A pinion 20 (Fig. 1) which is driven by any suitable power source, shown here as an electric motor 21 is journaled on the casting 14 to engage gear 17. A housing 22 is positioned on the casting 14 to enclose the gear 17, and sockets 23 are made integral with the housing for a purpose which will be hereinafter explained. v 7

Supported by lugs 24 (Fig. 3) on the gear 17 and rotatable therewith is a casing 25 whose bottom is formed with a circular aperture 26 surrounded, by an upstanding flange 27. A refractory bowl 28 rests on the upper edge of the flange 27 and is separated from thesides of the casing by insulating material 29, and formed in its bottom 'isan aperture 30 which registers with the aperture 26 in the casing. A ring 31 is bolted to thebottom of the casing 25 so that it underlaps the edge of the aperture 26 andsupports a refractory cone 32 which extends upwardly into the'intcrior of the bowl and snugly fits aperture 30. The upper end of the cone is formed with an inwardly extending annulus to' form a circular glass discharge orifice 33. v

Secured to the under side of the casting 14 their lower ends a fire-polishing and cooling unit positioned on the inside of the cone,

"concentric with the orifice 33. This unit consists 'of inner and outer cylinders 36 and 37 arranged in spaced concentric relation, the

lower ends of thesecylinders being connected ,byna base 38. The upperend of the inner cylinder 36 is flared outwardly, while the upper end of the outer cylinder 37 is turned inwardly at 39. Supportedon the inturned' are depending brackets 35 which supportat v portion 39 of the upper end of the outer cylindcr is a ring-shaped burner 40 the orifices of which are designed to project a flame against the glass at the point Where it emerges from the orifice 33 of the cone 32. Arranged in spaced concentric relation between the innerjand outer cylinders'36 and 37 are cylinders 41 and .42, the inner cylinder 41 being of less {height than the outer cylinder 42. Connected through the base 38 above' referred to with the space between the innerm st flared cylinder 36 and the shorter cylinder 4 1 is a'pipe 43;for admitting cold water to the space between the cylinders. A water I discharge pipe 44 is connected through the base 38 with the space between the cylinders 41 and 42 and a flue 45 leads from the space formed between the cylinder 42 and the outerwhich suitable burners placedi and the sides of. t

most cylinder 37 for drawing ofi the products of combustion of the burner 40 bymeans of a suction fan (not shown).

A casting 46 is supported above the bowl by means of standards 47 the lower ends of which are inserted in the socket 23 of the housing 22. The'casting is provided with an inwardly extending flange 49 supporting a refractory cover 50 which-is in part domeshaped withits lower ed e extending over the upper edge of the how 28. Outstanding portions of the cover contain ports 51 throu h not shown) may e v e cover extend parallel ig. 2) from the transverse center line of the apparatus and terminate in a pe 'ndicular wall 52 which is located in a l ilfne above the bowl 28 approximatel midway between its center and edge. his allows a portion of the bowl to remain open at 53 to act as-an inlet for the molten lass. The central portion of the cover is, ormed with an aperture 54 which is concentric with the cone itted in a socket at 56in the casting and extending upwardly therefrom is a hollow standard 1) and vertically slidable on the standard is an arm 57 carrying a perforated lug 58 which is movable on a screw threaded member'59 upon-which a nut 60 is adjustable to limit the downward movement of the. arm 57. cable 61 is made fast to the arm 57 and runs over a pulley 62 and down the inside of the hollow standard 55 to a suitable Windlass and ratchet means,

not shown) which is operated by a, hand wheel 63 (Fig. 2) to raise the arm 57. Formed ,on

i the outer end of the arm 57 is a collar 64 to .er 70 to be raised or lowered to va which a sleeve 65 is secured, and a claw piece 66 is clamped to the sleeve 65 for supporting a refractory sleeve 67 byi enga ex'nent with its flanged upger edge. f

heseeve 67, bein supported y the arm 57,; may be adjuste vertically by raisi and lowering the arm and when lowered, y reason of t 0 contact of the walls of thee rture in' the lug 58 with the screw threaded will beheld in concentric relation vto the orifice 33. An externallyscrew threaded pipe 68 fits inovably in the supporting sleeve 65, the threads on the pipe coacting with a threaded hand wheel supported on the top of collar 64. This pipe carries at its lower end, and supplies water to, a cooler 70 which consistspreferably of a cone-shaped water jacket. Extending into the jacket and concentric with the pipe 68 isa smaller pipe 71 which acts as an outlet for the water while concentric with this outlet pipe 71 and extending completely throu h the cooling means is an air-conducting tube 72 whose function will be hereinafter disclosed. Thehand wheel 69 enables the coolits distance from the glassflowing into e orifice member 59, the sleeve 69 which is rotatably' the-wallofthe tubing will be from is connected in any suitable manner with a discharge line for the waste water while the air con ucting tube 72 is connected to any suitable air supply.

When the apparatus is to be operated, it is placed with the inlet 53 under the forehearth 73 of a'furnace (not shown), the orifice 33 being positioned directly over a hole 74 in the floor upon which the apparatus is supported. Located in the room below is a suitable tractor 75, such closed .in the; application of William J. Woods, Ser. No. 353,890 filed Apr. 9, 1929.

In operation the. bowl 28 is rotatedat a constant rate of speed by the motor 21, and a stream of molten glass 76, regulated by a suitable gate 77 according to the size of the tubing to be drawn, flows into the -bowl.28 from the forehearth 73. The glass flows rises inside of the sleeve,-

the exposed surface 78 of the glass 76. "The molten lass in the bowl is kept at such a height t at its upper surface lies in a plane above the upper end of the cone 32 and hence the glass will flow over the edge of the cone andrthrough the orifice 33 whlch is large enough in diameter to keep the bore of the tube open, the plastic glass passing downwardly through the cone 32 and the cylinder 36. A steady flow of air is maintained through the tube 72 to create a draft through the bore of the.tubing, thereby roducing a downward flow of air between-t and the surface of the glass at 78 which augments the heat absorbing action of the cooler. This downward draft inside the tubing also tends to cool the inside surface thereof for some distance below the bowl and hastens the hardening of the tubing. When the tubing emerges from the cylinder 36, it is directed through the hole 74 in the floor to thetractor by means of whioh it is drawn to size. This ulling operation maybe accomplished by and, or at times. by avity, but it has been found that a mechanical apparatus operating at a predetermined rate 'ofTsgeed will produce the best results.

as is more fully dise cooler70.

lasticity for drawe'. cone 32 and the Sincethe layer ofv glass *which is uppermost during the.

drawing operation eventually becomes the inside wall of the tube without contac with any hard unyielding surface,'-it is not liable to injury or striation durinlg the drawa ing operation and consequently e inside of perfections. By'means of the hand wheel 63 and the nut the verticalposition of. the sleeve 67 may be so adjusted that the height of the-glass in relation to the orifice 31 may be maintained and hence sufiicient glass will flow over the edge of this orifice to build up the wall of the tube 7 9 to the desired thick- Owing to the initial temperature of the molten glass (6 and the cooling action of the cooler 70, the temperature of the glass flowover the edge of the orifice 33 increases with its de th or its distance from the cooled upper surface la er of as which forms the inside surface oi the tu is sufiicien tly cooled to support the drawin operation, the glass which contacts the go of thee orifice and forms the 1 outside of the tube may have sufiicient fluidity .9 to heal u any-striations which ma be formed thereon ht irregularities -o the orifice. ,The flamgf r n the burner 40 is directed so 'asto heat the orifice and also'the surface of the glass as it leaves the orifice, thereby aug suficiently'to cause this healing operation to take place before the tube passes into the cylindex 36, where the cooling action of the water .as it flows between the cylinders 36'and 41 causes the tubeto be appreciably cooled. This cooling action hastens the hardening of the tube. which-is comtpleted b the absorption of the heat'from e tube ythe air beexercises an influence on the diameter of the.

tubing as an increased viscosity results in an increase of diameter.

When drawing tubing of large diameter, it may be found necessary to admit air under pressure to the inside of the tube whereupon alarge amount of'ain-may be forced through the air conducting tube 7 2', but in the production of small tubing this is usually unnecesthat the eight of the glass in relation'to the orifice 33, the condition of the glass at 7 8 and the speed of movement of the tractor 75, may be so adjusted in relation to each other as to rapidly produce perfect tubing of the desred dimensions. The bowl 28 may be rotated at a'constant-rate of sfpeed by the motor 21 to the temperature and. 6 volume of the glass as it flows over the cone 32 insure uniformity 0 at 78, Therefore-while the menting the initial temperatureof the glass low the bowl. Since the tubing is in a plastic ry. B experiinentationit will 'be found and'out of the orifice 33. Tubing .of very recise dimensions throughout may be prouced in this manner, but when less exacting requirements are to be met, I have found that good results may be obtained without rotatmg the bowl or even by utilizing a stationary container for the molten glass.

While the above disclosure sets out a specific embodiment of my invention, I consider that various changes in structure may be made without violating the spirit of my invention and limit myself only to the scope of the appended claims. a

It will 'be noted that the refractory cone 32 forms an annular curb arising from the bottom of the glass container or bowl 28 and surrounding a downwardly discharging orifice and that the molten glam contained in the latter flows over the crest of such curb into the orifice and in so flowing forms a hollow stream, the inner surface of which is exposed to the cooling radiation of the cooler 70. Thus in the practice of myinvention the 'tube','as distinguished from the-molten glass in the container, does not have its interior surfacein contact with refractory material or a forming element of any kind but such wall or'su-rface is due entirely to the natural flow of the glassover the crest of the curb.

Hence the interior of the tube has a high finish while the exterior of the tube, which has been in contact with the crest of the curb, is refinished by the burner 40.

What I claim is 1. 'In a glass tube making apparatus, a container for molten glass having an outlet orifi ce for the lass, means for cooling a portion-of the g ass in the container, and means 'surroundi the orifice for causing the molten glass w ichissues through it to assume the form of a hollow stream.

2. In a glass tubedrawing apparatus, a container the nipple,'cooling means in the sleeve, and

means; for ,drawing glass downwardly through the nipple.

' 3. a glass tube making apparatus,.-a

covered container for molten glass, a nipple projecting upwardly in the container, a sleeve extendmg throu h the cover into the container concentricalfy' with the 'nipple, means to cause a draft of air from outside thecontainer to flow over the surface of the glass inside the sleeve and cool a portion of the glass, and means to drawthe cooled portion downwardly through the nipple.

4. .In a tube drawing machine the combination with a container for molten glass having a hollow curb arising from the fio'or thereof and forming an outlet, of a sleeve, whose lower diameter is substantially larger than the exterior diameter of the curb at its top, projecting into the glass from above, the

or molten glass having an outlet. or fice, an upwardly projecting nipple in said orifice, a depending sleeve concentric with sleeve being open to atmosphere, a member located in the curb and out of contact with the glass flowing therethrou h, and means for introducing air into the interior of thetube formed by the curb below such member.

5. In an apparatus for the manufacture of glass tubing, the combination with a container having a downwardl directed orifice formed by an annular cur thereof, a cooled element located within the curb, and means for so re latin the rate of flow over the crest of t e cur that the glass moves thereover from the container in an annular stream out of contact with the cooled element.

6. In an apparatus for the manufacture of glass tubing, the combination of a container for molten glass having adownwardly directed orifice formed by an annular curb in the bottom thereof, and a vertically adjustable sleeve concentric with the orifice and projecting into the glass from above'and havmg a greater diameter than the crest of the curb.

7. In an apparatus for the manufacture of glass tubing,.the combination of a container having a downwardly directed orifice formed by an annular curb in the bottom thereof, means for rotating the container around the axis of the orifice, and means for so regulating the head of glass over the crest of the cur that the glass moves thereover and downwardly through the orifice in a hollow stream.

8. In an apparatus for the manufacture of glass tubing, the combination of a container having a downwardly directed orifice formed by an annular curb in the bottom thereof, means for rotating the container around the axis of the orifice, means for so regulating the head of glass over the crest of the curb that the glass moves thereover and downwardly through the orifice in a hollow stream, and a heater located below the orifice and acting on the exterior surface of the glass issuing therefrom.

9. In an apparatus for the manufacture of glass tubing, the combination of a container having a downwardl directed orifice formed by an annular curb 1n the bottom thereof, a cooled element located within the curb, and a vertically adjustable sleeve concentric with the orifice and projecting into the glass from above and havin a greater diameter than the crest of the curb, so regulating the rate of flow over the crest of the curb that the glass moves thereover from the container in a hollow stream out of contact with the cooled element.

10. In an apparatus for the manufacture of glass tubing, the combination of a container having a downwardly directed orifice formed by an annular curb in the bottom thereof, a cooled element located within the curb, means for so regulating the rate of flow over the crest of the curb that the glass moves thereover in the bottom' from the container in a hollow stream out of contact with the cooled element, and means for. rotating the container around the axis of the orifice.

11.- In an ap aratus for the manufacture of glass tubing, t e combination of a container having a downwardly directedorifice formed by an annular curb in the bottom thereof, a cooled element located within the curb, means for so regulating the rate of flow over the crest of the curb that the glass moves thereover from the container in a hollow stream out of contact with the cooled element, and a heater located below the orifice-and acting on the exterior surface of the glam issuing therefrom. 7

12. In an ap aratus for the manufacture of glass tubing, t e combination of a container having a downwardl directed orifice formed by an annular curb in the bottom thereof, a vertically adjustable sleeve concentric with the orifice and projecting into the glass from above and having a greater diameter than the crest of the curb, and means for rotating the container around the axis of the orifice.

13. In an apparatus for the manufacture of glass tubing, the combination of a container having a downwardl directed orifice formed by an annular curb in the bottom thereof, a vertically adjustable sleeve concentric with the orifice and projecting into the glass from above and having a greater diameter than the crest of the curb, and a heater located below the orifice and acting on the exterior surface of the glass issuing therefrom.

' 14. In an apparatus forv the manufacture of glass tubing, the combination of a container having a downwardly directed orifice formed by an annular curb in the bottom thereof, a

cooled element located within the curb, a vertically adjustable sleeve concentric with the orifice and projecting into the glass from above and having a greater diameter than the crest of the curb, for so regulating the rate of flow over the crest of the curb that the glass'moves thereover from thecontainer in a hollow stream out of contact with the cooled element, and means for rotating thecontainer around the axis of the orifice.

15. In an apparatus for the manufacture of glass tubing, the combination of a container having a downwardly directed orifice formed.

by an annular curb in the bottom thereof, a cooled element located within the curb, a vertically adjustable sleeve concentric with the orifice and projecting into the glass from above and having a greater diameter than the crest of the curb, for so regulating the rate of flow over the crest of the curb that the glass moves thereover from the container in a hollow stream out of contact with the cooled element, and means for introducing air under pressure into the tube below the cooling member.

16. The hereinbefore described method of making glass tubing which comprises flowing glass from a reservoir of molten glass over the crest of an annular curb in a hollow v stream, the interior surface of the annular stream being free of contact with a former and chilling suchinterior surface by radia tion.

17. The hereinbefore'described method of making glass tubing which comprises flowing glass from a reservoir of moltenv glass over the crest of an annular curb in a hollow stream, the interiorsurface of the stream being free of contact with a former and chilling such interior surface by radiation, and by currents of cold air.

18. The hereinbefore described method of making glass tubing which comprises flowing glass from a reservoir of molten glass over the crest of an annular curb, so limiting the rate of flow that the orifice formed by the annular curb is not filled by the flowing glass, and chilling the interior surface of the hollow glass at the curb by radiation from a chille member located within the curb;

19. The hereinbefore described method of making glass tubing which comprises flowing glass from a reservoir of molten glass over the crest of an annular curb, limiting the rate of flow over such curb so that the orifice is not filled with flowing glass, and controlling the thickness of the tube so formed by determining the rate of flow over the crest of the curb.

WALTER C. WEBER. 

